On Almost alpha-Cosymplectic Manifolds with some Nullity Distributions

Hakan Ozturk 호남수학회 2019 호남수학학술지 Vol.41 No.2

The object of the paper is to investigate almost alpha-cosymplectic $(\kappa,\mu ,\nu )$ spaces. Some results on almost alpha-cosymplectic $(\kappa ,\mu,\nu )$ spaces with certain conditions are obtained. Finally, we give an example on $3$-dimensional case.

ON ALMOST ALPHA-COSYMPLECTIC MANIFOLDS WITH SOME NULLITY DISTRIBUTIONS

Ozturk, Hakan The Honam Mathematical Society 2019 호남수학학술지 Vol.41 No.2

The object of the paper is to investigate almost alpha-cosymplectic (${\kappa},{\mu},{\nu}$) spaces. Some results on almost alpha-cosymplectic (${\kappa},{\mu},{\nu}$) spaces with certain conditions are obtained. Finally, we give an example on 3-dimensional case.

Prevelance of Common YMDD Motif Mutations in Long Term Treated Chronic HBV Infections in a Turkish Population

Alagozlu, Hakan,Ozdemir, Ozturk,Koksal, Binnur,Yilmaz, Abdulkerim,Coskun, Mahmut Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.9

In the current study we aimed to show the common YMDD motif mutations in viral polymerase gene in chronic hepatitis B patients during lamivudine and adefovir therapy. Forty-one serum samples obtained from chronic hepatitis B patients (24 male, 17 female; age range: 34-68 years) were included in the study. HBV-DNA was extracted from the peripheral blood of the patients using an extraction kit (Invisorb, Instant Spin DNA/RNA Virus Mini Kit, Germany). A line probe assay and direct sequencing analyses (INNO-LIPA HBV DR v2; INNOGENETICS N.V, Ghent, Belgium) were applied to determine target mutations of the viral polymerase gene in positive HBV-DNA samples. A total of 41 mutations located in 21 different codons were detected in the current results. In 17 (41.5%) patients various point mutations were detected leading to lamivudin, adefovir and/or combined drug resistance. Wild polymerase gene profiles were detected in 24 (58.5%) HBV positive patients of the current cohort. Eight of the 17 samples (19.5%) having rtM204V/I/A missense transition and/or transversion point mutations and resistance to lamivudin. Six of the the mutated samples (14.6%) having rtL180M missense transversion mutation and resistance to combined adefovir and lamivudin. Three of the mutated samples (7.5%) having rtG215H by the double base substituation and resistance to adefovir. Three of the mutated samples (7.5%) having codon rtL181W due to the missense transversion point mutations and showed resistance to combined adefovir and lamivudin. Unreported novel point mutations were detected in the different codons of polymerase gene region in the current HBV positive cohort fromTurkish population. The current results provide evidence that rtL180M and rtM204V/I/A mutations of HBV-DNA may be associated with a poor antiviral response and HBV chronicity during conventional therapy in Turkish patients.

The evaluation with ANSYS of stresses in hazelnut silos using Eurocode 1

Kibar, Hakan,Ozturk, Turgut Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.51 No.1

In this study, the optimum silo dimensions for the barrel-type steel-concentrated silo with a conical outlet port usable in the hazelnut storage were investigated. Three different types of silo models as Model 1 (1635 tons), Model 2 (620 tons) and Model 3 (1124 tons) were used in the study. Varying wall thicknesses were used for Model 1 (10, 11, 12, 13, 14, 15 and 20 mm), Model 2 (10, 15 and 20 mm) and Model 3 (10, 15 and 20 mm) silos. For Model 1 silo has the most storage capacity here, to determine its optimum wall thickness, the wall thicknesses of 11, 12, 13 and 14 mm were used as different from the other models. Thus the stresses occurring in different lines with ANSYS finite element software were examined. In the study it was determined that the 10, 11 and 12 mm wall thicknesses of the Model 1 silo are not safe in terms of the stresses caused by the vertical pressure loads in the filling conditions. From the view of the filling and discharge conditions, other wall thicknesses and model silos were diagnosed to be secure. The optimum silo dimensions which won't cause any structural problems have been found out as the Model 1 silo with a 13 mm wall thickness when the filling capacity and the maximum von Mises stresses are taken into account. This barrel-type silo with conical outlet port sets forth the most convenient properties in hazelnut storing in terms of engineering.

Letter tothe editor : The Cumulative Colectomy Rate in Patients with Cytomegalovirus-Positive Ulcerative Colitis

( Kadir Ozturk ),( Hakan Demirci ),( Murat Kantarcioglu ),( Ahmet Uygun ),( Sait Bagci ) The Editorial Office of Gut and Liver 2015 Gut and Liver Vol.9 No.2

Antithrombotic effect of epigallocatechin gallate on the patency of arterial microvascular anastomoses

Igde, Murat,Ozturk, Mehmet Onur,Yasar, Burak,Bulam, Mehmet Hakan,Ergani, Hasan Murat,Unlu, Ramazan Erkin Korean Society of Plastic and Reconstructive Surge 2019 Archives of Plastic Surgery Vol.46 No.3

Background Microvascular anastomosis patency is adversely affected by local and systemic factors. Impaired intimal recovery and endothelial mechanisms promoting thrombus formation at the anastomotic site are common etiological factors of reduced anastomosis patency. Epigallocatechin gallate (EGCG) is a catechin derivative belonging to the flavonoid subgroup and is present in green tea (Camellia sinensis). This study investigated the effects of EGCG on the structure of vessel tips used in microvascular anastomoses and evaluated its effects on thrombus formation at an anastomotic site. Methods Thirty-six adult male Wistar albino rats were used in the study. The right femoral artery was cut and reanastomosed. The rats were divided into two groups (18 per group) and were systemically administered either EGCG or saline. Each group were then subdivided into three groups, each with six rats. Axial histological sections were taken from segments 1 cm proximal and 1 cm distal to the microvascular anastomosis site on days 5, 10, and 14. Results Thrombus formation was significantly different between the EGCG and control groups on day 5 (P=0.015) but not on days 10 or 14. The mean luminal diameter was significantly greater in the EGCG group on days 5 (P=0.002), 10 (P=0.026), and 14 (P=0.002). Intimal thickening was significantly higher on days 5 (P=0.041) and 10 (P=0.02). Conclusions EGCG showed vasodilatory effects and led to reduced early thrombus formation after microvascular repair. Similar studies on venous anastomoses and random or axial pedunculated skin flaps would also contribute valuable findings relevant to this topic.

Is catechol-o-methyltransferase gene polymorphism a risk factor in the development of premenstrual syndrome?

Deveci, Esma Ozturk,Incebiyik, Adnan,Selek, Salih,Camuzcuoglu, Aysun,Hilali, Nese Gul,Camuzcuoglu, Hakan,Erdal, Mehmet Emin,Vural, Mehmet The Korean Society for Reproductive Medicine 2014 Clinical and Experimental Reproductive Medicine Vol.41 No.2

Objective: The objective of this study was to investigate whether there was a correlation between catechol-o-methyltransferase (COMT) gene polymorphism, which is believed to play a role in the etiology of psychotic disorders, and premenstrual syndrome (PMS). Methods: Fifty-three women with regular menstrual cycles, aged between 18 and 46 years and diagnosed with PMS according to the American Congress of Obstetrics and Gynecology criteria were included in this study as the study group, and 53 healthy women having no health problems were selected as the controls. Venous blood was collected from all patients included in the study and kept at $-18^{\circ}C$ prior to analysis. Results: There was no significant difference between the groups in terms of demographic features such as age, body mass index, number of pregnancies, parity, and number of children. No statistically significant difference was observed in terms of COMT gene polymorphism (p=0.61) between women in the PMS and the control groups. However, a significant difference was found between arthralgia, which is an indicator of PMS, and low-enzyme activity COMT gene (Met/Met) polymorphism (p=0.04). Conclusion: These results suggested that there was no significant relationship between PMS and COMT gene polymorphism. Since we could not find a direct correlation between the COMT gene polymorphism and PMS, further studies including alternative neurotransmitter pathways are needed to find an effective treatment for this disease.

Gallstone Disease Does Not Predict Liver Histology in Nonalcoholic Fatty Liver Disease

( Yusuf Yilmaz ),( Talat Ayyildiz ),( Hakan Akin ),( Yasar Colak ),( Oguzhan Ozturk ),( Ebubekir Senates ),( Ilyas Tuncer ),( Enver Dolar ) 대한소화기학회 2014 Gut and Liver Vol.8 No.3

Background/Aims: We sought to examine whether the presence of gallstone disease (GD) in patients with biopsy-proven nonalcoholic fatty liver disease (NAFLD) is associated with liver fibrosis and histological nonalcoholic steatohepatitis (NASH) score. Methods: We included 441 Turkish patients with biopsy-proven NAFLD. GD was diagnosed in the presence of sonographic evidence of gallstones, echogenic material within the gallbladder with constant shadowing and little or no visualization of the gallbladder or absence of gallbladder at ultrasonography, coupled with a history of cholecystectomy. Results: Fifty-four patients (12.2%) had GD (GD+ subjects). Compared with the GD- subjects, GD+ patients were older, had a higher body mass index and were more likely to be female and have metabolic syndrome. However, GD+ patients did not have a higher risk of advanced fibrosis or definite NASH on histology. After adjustment for potential confounding variables, the prevalence of GD in NAFLD patients was not associated with significant fibrosis (≥2) (odds ratio [OR], 1.06; 95% confidence interval [CI], 0.53 to 2.21; p=0.68) or definite NASH (OR, 1.03; 95% CI, 0.495 to 2.12; p=0.84). Conclusions: The presence of GD is not independently associated with advanced fibrosis and definite NASH in adult Turkish patients with biopsy-proven NAFLD.

Parafibromin Staining Characteristics in Urothelial Carcinomas and Relationship with Prognostic Parameters

Serap Karaarslan,Banu Yaman,Hakan Ozturk,Banu Sarsik Kumbaraci 대한병리학회 2015 Journal of Pathology and Translational Medicine Vol.49 No.5

Background: Parafibromin is a recently defined tumor suppressor gene. The aim of our study was to determine the relationships of parafibromin expression in urothelial carcinomas (UCs) with prognostic parameters and to evaluate the use of parafibromin as a potential marker of UC. Methods: Parafibromin expression was assessed in 49 UC specimens using immunohistochemistry. The correlations between parafibromin expression and clinical and pathologic parameters were investigated. Results: Of the patients, 42 (85.7%) were male, and the mean age was 69.6 ± 8.2 years (range, 54 to 88 years). Morphologically, the UCs were divided into two groups: papillary (n = 27) and non-papillary (n = 22). There were seven low-grade (14.3%) and 42 high-grade (85.7%) tumors. Parafibromin was negative in 13 tumors (26.5%), partially positive in 19 tumors (38.8%), and positive in 17 tumors (34.7%). Parafibromin expression was more negative in UCs from upper urinary locations (n = 17) and with muscularis propria invasion (n = 28), which was statistically significant (p = .009 and p = .007, respectively). There was no statistically significant relationship between parafibromin expression and gender, age, tumor grade, survival, or disease-free survival. Conclusions: We found that UC cases with parafibromin positivity had less of a tendency to show muscularis propria invasion and were more commonly located in the lower urinary system. These results need to be confirmed with studies based on larger case series.

A new approach to determine the moment-curvature relationship of circular reinforced concrete columns

Naci Caglar,Aydin Demir,Hakan Ozturk,Abdulhalim Akkaya 사단법인 한국계산역학회 2015 Computers and Concrete, An International Journal Vol.15 No.3

To be able to understand the behavior of reinforced concrete (RC) members, cross sectional behavior should be known well. Cross sectional behavior can be best evaluated by moment-curvature relationship. On a reinforced concrete cross section moment-curvature relationship can be best determined by both experimentally or numerically with some complicated iteration methods. Making these experiments or iterations manually is very difficult and not practical. The aim of this study is to research the efficiency of Neural Networks (NN) as a more secure and robust method to obtain the moment-curvature relationship of circular RC columns. It is demonstrated that the NN based model is highly successful to determine the moment-curvature relationship of circular reinforced concrete columns.